Dead Ignition System

I come here trying to save an engine in a vehicle that I have had half of my life. If I can't get through this problem myself I will have to do the dreaded deed of feeding it to the wolves (taking it to a garage) where they will no doubt charge me inaccordance to whatever they want, if they can even fix the problem themselves.

Whatever help I can get here will be deeply appreciated.

This is a Chevy Van 305 V8 with an HEI ignition system that is producing no spark. I have replaced everything at one time or another. At this time it now has a pretty much new ignition system. New ignition switch, distributor (which came with a new module, pick-up coil and capacitor), new distributor cap and rotor and a new coil. There is also now new plugs and wires.

There is 12 volts present (with switch in 'run' position) at the connector which plugs into the 'bat' terminal of the cap. While trying to crank the engine it drops to around 10 volts. I would think this is normal, no?

Please help. I am at my wits end. Does anybody have any suggestions?

What year is it? If it has a computer, try replacing it with another known working computer. The computer doesn't provide spark, but it controls the curve and if its shorted or otherwise damaged it might not allow proper spark.

Try the solenoid on the starter. It supplies voltage during cranking. Wire up a hot wire directly from the battery to the distributor and see if it will run that way. If it does, then you're not getting enough cranking voltage from the solenoid. Try replacing the solenoid (best to just buy a whole starter) and give it another shot.

Not to doubt you, but how have you determined that there is no spark produced? Is there no spark, or is there no spark getting to the plugs? Has the van been on a scope? If there is truely no spark, then it is very likely a primary-side problem. Things such as bad module, bad pick-up, no power to module, etc. A tie to the computer (if it has one) should not be a concern at cranking speed, since the module will trigger internally until it's running. I think it switches around 600rpm, but it's been a long time. Doesn't rule if out, but moves it down the list. To test for a functioning primary side, you could plug a tach into the tach connector on the HEI. If it moves, you've eliminated the entire primary side. If it doesn't, you know where to start. If the primary side is working, move on to the coil. A scope is the safest way to see if it is firing. Let's assume the coil is working for now. Have you pulled a wire to check for a spark? If so, don't do it again. If not, don't do it! The reason is that on HEI systems, the spark WILL find a ground. With the wire pulled it may arc through the rotor to the distributor (This happens A LOT. Look for a burn mark on the rotor bottom) It can also carbon track in several different places inside the cap...none of which are good. 10 volts during cranking is fine. Now for the "insulting" questions... There is a wire or metal strap that grounds the coil. It's the middle prong on the power connector. Did you put it in place? Did you put the new button in the cap correctly? (button first, rubber ring second) Even pros oops this now and then. Is the distributor turning? Sorry, but gotta cover all the bases. :) I would suggest a trip to the nearest scope if the primary works. It will likely cost less than throwing parts at it, and saves a lot of time. If you have more information, please submit it.

Wow, you guys are good here!!

Curtis, I was thinking about trying that direct wiring from the battery.

After plenty of thought last night, I decided to quit putting off researching these four wires that are coming out of the distibutor. That's probably why I never mentioned them before. Three of them connect into the input side of the electronic ignition module along with the two pick-up coil leads. Following these wires out of the distributor leads into a small metal box with a circuit board inside. It is underneath the drivers seat. My manual is calling it the ECM. Apparently all it is for(with my vehicle, 1983, by the way) is to receive one input from a knock sensor. I began messing around with this and low and behold the engine started?!!?

The problem is still intermittent, though. I stopped and started the engine several times. Sometimes it wouldn't start again (meaning absolutely no spark and benchtest I did come to that conclusion by grounding a plug. I had no idea that wasn't a wise thing to do. Apparently neither does Cheverlot since that is a method they suggest in their manual) until after some flexing and bending of the wires. A couple of times without even touching anything the engine just stopped!!

So I think I have isolated the problem but I do not know if it could be this ECM (hope not, $100.00), the knock sensor or bad wiring.

Any suggestions?

P.S. Your guys post were so lock, stock full of good information I am printing them out and putting them into my manual :-)

It sounds like a wiring problem if wiggling makes a difference. I'm beating my head against the wall trying to remember a wiring fix for this. As I recall, we used to jumper two wires on the 4-wire connector to bypass the knock system. I can't remember which wires and I don't have a van manual. (We did this on engines with noisey valvetrains/fuel pumps that would trigger the knock sensor, and weren't worth fixing.) Does the distributor have a vacuum advance on it? Have you tried to start it with the 4-wire connector unplugged?

FYI - the ECM watchs a few sensors in today's world, but seeing its a 83, i could see the knock sensor being the only input. if the computer detects knocking (like pre-ignition or detenation) the computer will advance(or is it retard? i always forget) the ignition timing to start the burn earlyier in an effort to reduce or prevent the knock.

BTW i have never worked on a HEI or any distribior system before(DIS ROCKS!), but i have heard of dissconnecting the 4-wire connector as a diagnostic test as stated above

The KS would retard the spark if it was hearing it. The ECM controls more than just KS. By 83 it controlled idle fuel mixture (the wires going into the fuel bowl on the Q-jet carb), the KS, and the ignition curve. Pull the connector off the ECM and see if you get zinc snow... that's what I call it. Sometimes the zinc plating on the pins of the ECM flakes off. If that's the case, find a junkyard replacement and drive away. If you're messing with the wires and its dying, then there is definitely a problem with wires or the ECM. It could be a cold solder in the ECM, a wire or connection, or for that matter a bad ground somewhere.

Yes, there is vacuum advance on it. I have tried to start with the connector just outside the distribtor disconnected. That is where and when I started suspecting something about this ECM. I seem to remember hearing a clicking sound coming from somewhere when I would reconnect it while the ignition was in the 'run' position. This made me follow the wires and then began messing around with this ECM.

This ECM apparently and oddly enough seems to disallow any output from the ignition module. That is just a guess but bottom line is a no spark condition. So this ECM apparently must be connected inorder for any current to reach the plugs. The manual says it will retard the spark so the mechanical advance can maximize inorder to eliminate any detonation under a heavy load. I wonder how or why it disables spark because I'm definently unable to start the engine without it hooked up?

I plan to try checking for continuity of these wires today to see if there is any funny business going on with them. The connector on the ECM grips the terminals on the card hard enough to leave gouge marks in them so I figure the intermittency would not be there since it looks like a pretty solid connection. Everything else about the card looks clean.

Nobody mentioned the knock sensor itself. Couldn't that be a possible source of intermittency or problem?

I would definently consider bypassing this feature since as far as I can tell there is only the one input into this thing. I very seldom put a heavy load on this engine.

Thanks again for all your help, fellas.

Well, I have reached the point of no return. After many failed attempts to again restart the engine I am now giving up. I can't get a consistent spark and the sparks that I do see are kind of orangish/whitish, of which I understand indicates a weak spark.

There really is no way to get a known good ECM without buying one.
Autozone told me that once I do, it is mine to have and hold and the only thing they would do is to replace with another one. The same holds true with the distributor I got from them.

So instead of throwing more money/new-parts at it I have been recommended a reputiple and well-equipped garage that I will have to tow the van to and more than likely pay out a large sum of money to get it back on the road. Ho-Hum.

This is a big blow to this one do-it-yourselfer. I thought I could get to the bottom of any problem with this vehicle but after doing all I am capable of all I get is "errrr errrr errrr errrr errrr errrr errrr".

Thanks for all you help again and I'll be sure to let you know what ends up happening.

You have the option of installing an older stand-alone distributor, if you can find one.

I still have my old one that I haven't returned to get the core charge for. Autozone won't just give me my money back for the new one so I am stuck with the new one. The problem started with the old one. It continues with the new one. I now have new everything. I don't have the equipment to be able to look inside anything other than a voltmeter. Nothing I have checked tells me anything is wrong.

The shop I take it to is NOT going to change one part without my consent. If they tell me the problem has anything to do with any new part I have already installed then that is covered under the Autozone warrenty. If they tell me its the ECM I will then get one MYSELF from somewhere, maybe Autozone again. Nobody is going to rip me off, if I can help it except for maybe the towing company (I can't help that, I have no choice there :-)

Wish me luck and thanks again.

Good news, fellas!! Namely Curtis and benchtest who hung with me through this problem.

If you can imagine Garfield's big sh*t eatin' grin, Snoopy's dance and Steve Martins happy feet all mixed into one, you've got a vision of me now!

Thanks for your input which in a big way helped me into sticking with it. It was right at the connector on the ECM. I was in the process of putting the circuit board back into its metal box and then back underneath the seat in preparation to tow it to a garage when I decided to try and start it again. It fired. OK!! ITS GOT TO BE HERE!!!

Looked at the zinc terminals on the card again. Decided to look at them through a magnifying glass. Those gouges that I mentioned earlier that were telling me there was a good connection turned out to be canyons, instead. Upon inspection of the connector terminals there was evidence of the same thing. SO!! maybe the current has finally decided that it could not consistently bridge the gap. I got out the trusty soldering iron and layed a layer of solder on each gouge to fill them in. BINGO!!
After some fiddling with the distributor, she's purring like a kitten.

WHEW!! I even took back some parts from shotgunning my problem that I was left over with to Autozone and they gave me my money back. $125.00 worth! (it helped that the guy that serviced me was on his last day and on his way to live in the Florida Keys!! HA-HA-HA!!!)

So my soldering iron fixed the problem. I end up with a new distributor (which also includes new ignition module, new pick-coil and new capacitor) new cap and rotor and new plugs and wires. NO PROBLEMO! I might never need to be concerned about them again.

So all's well that end's well. Thanks guys, for your invaluable input! Even a competent mechanic would have had trouble with that one which would have cost me a few jacks.